如果Akamai边缘服务器缓存了一个网址，它是否会与其他边缘服务器共享该内容，或者本地缓存内容的边缘服务器是否会返回原始内容以获取内容？
我很乐意为此制作一份官方的Akamai文件，但当然会欣赏任何意见！
请注意，我已经尝试了这一点，并且看到了我期望的答案 - 边缘服务器将至少在某些时间返回原点来获取内容，即使它位于另一个边缘服务器上。
例如，我在整个周末都停留了一个curl来请求一个缓存7天的资源，并且看到我有3个不同的缓存响应（不同的响应头），并且可以看到原点必须是＃ve; ve被访问过至少3次，
$ cat /t/akamai_dump_requests_all_weekend.txt | grep x-rate-limit-reset| sort | uniq -c
259 < x-rate-limit-reset: 1489776484
1 < x-rate-limit-reset: 1489779291
12 < x-rate-limit-reset: 1489781137
我也看到我的转储中列出了很多不同的边缘服务器，不过这是正常的，我认为。
66 a80-12-96-140.deploy.akamaitechnologies.com
65 a204-237-142-14.deploy.akamaitechnologies.com
51 a204-237-142-44.deploy.akamaitechnologies.com
38 a80-12-96-230.deploy.akamaitechnologies.com
8 a65-158-180-197.deploy.akamaitechnologies.com
6 a23-58-92-92.deploy.akamaitechnologies.com
6 a23-58-92-39.deploy.akamaitechnologies.com
5 a65-158-180-190.deploy.akamaitechnologies.com
5 a64-145-68-25.deploy.akamaitechnologies.com
5 a64-145-68-15.deploy.akamaitechnologies.com
4 a65-158-180-180.deploy.akamaitechnologies.com
4 a204-141-247-173.deploy.akamaitechnologies.com
4 a204-141-247-143.deploy.akamaitechnologies.com
2 a66-110-100-23.deploy.akamaitechnologies.com
1 a72-37-154-53.deploy.akamaitechnologies.com
1 a23-61-206-205.deploy.akamaitechnologies.com
1 a205-185-195-182.deploy.akamaitechnologies.com
答案 0 :(得分：2)
我在这里没有得到答案，所以I posted this same question on the Akamai Community Forums，得到了来自Akamai高级解决方案架构师Neil Jedrzejewski的以下回复。谢谢尼尔！
First of all, which edge server answers a request will vary over time based on
our low-level mapping system and load in a specific network region. Don't read
too much into the fact that you get many different edge servers - swapping them
in and out is part and parcel of how we give our customers scale and
availability.
To answer your question about shared caching, a high level explanation goes like
this.
When a client makes a request our mapping system will return the IP address(es)
of an edge server best located to honour the request. These edge servers are
grouped together in what we call network "regions". If a specific edge server
receives a request and cannot fulfil it from it's own cache, it will send out
a broadcast message (ICP) on it's back-plane asking if any other edge machine
peers in the same region has the object. The timeout for a response to this
request is very short (as the request is local) and if a peer has it, it will
pass the request to the peer and served the response before caching it
locally.
If no local peer is able to satisfy the request, the edge machine will them go
forward to it's cache parent as a new client request and the parent will attempt
to satisfy the request (again, checking with it's own ICP peers), serving the
object out of cache to the edge machine. The edge machine will then serve it
back to the client and cache it locally for next time. If the object is
unavailable or invalid (read: TTL expired) along the entire cache hierarchy
chain, then yes, it will go back to origin to re-validate or reacquire the
object.
An important point to remember is that caching is "best effort" only. Although
your TTL for an object was 7 days, that is simply an instruction to the cache on
how long to consider the content "fresh" and a valid response for a request.
However it is not a guarantee that the object will remain in a servers cache.
Objects can and will drop out of cache if they are infrequently requested or due
to other operational factors. This is where ICP and parent caches help because
they help consolidate requests. So although an object may drop out of a specific
edge cache, it may well still be in the cache parent as many edges are passing
requests through it thus giving a high cache-hit ratio.
So in short, our caching system. Will use different edge machines to respond to
a request over time based on our mapping systems insight into which machine will
best serve the client request. Will ask a local peer if it has a copy of an
object if it cannot satisfy the request itself. Will forward the request to a
cache parent if necessary to fulfil the request. Will go back to origin for the
object if the object is "stale" or if itself, a peer or parent cannot satisfy
the request.
Hope that helps.